[Intravascular stents in the treatment of congenital cardiopathy].
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Follow-Up Studies↗
Biomedical subjects
L Ballerini
Publications and source records attributed to L Ballerini.
Electrophysiological interactions between 5-hydroxytryptamine and thyrotropin releasing hormone on rat hippocampal CA1 neurons.
Intracellular recording from CA1 neurons of the rat hippocampal slice preparation was used to examine the possibility of functional interactions between 5-hydroxytryptamine (5-HT) and thyrotropin releasing hormone (TRH), which act as cotransmitters in other areas of the central nervous system. 5-HT (30 microM) elicited complex effects consisting of biphasic changes in membrane potential and a strong depression of the afterhyperpolarization (AHP) following a spike burst. TRH (10 microM) did not alter membrane potential or input conductance but it produced a partial block of the AHP. Under single-electrode voltage clamp, 5-HT and TRH both reduced the amplitude of voltage-activated total K+ currents. When the two substances were co-applied, their actions were occluded. The voltage-activated K+ current remaining in Ca(2+)-free solution lost its sensitivity to 5-HT and TRH, suggesting that the K+ current modulated by TRH and 5-HT was Ca(2+)-dependent, although TRH itself did not depress high-threshold voltage-activated Ca2+ currents. When a relatively small concentration (5 microM) of 5-HT was co-applied with an equimolar amount of TRH, the degree of block of the spike AHP was the sum of the two individual effects of these drugs. It is suggested that in hippocampal pyramidal cells 5-HT and TRH influenced neuronal excitability by depressing a Ca(2+)-dependent K+ current, a phenomenon perhaps mediated through a common intracellular second messenger pathway.
Animals↗
EPSP-spike potentiation during primed burst-induced long-term potentiation in the CA1 region of rat hippocampal slices.
Long-term potentiation induced by high-frequency stimulation in the CA1 region of the hippocampus exhibits EPSP-spike potentiation. This consists of an increase in population spike amplitude exceeding that predicted by EPSP potentiation alone. This phenomenon is apparently due to an increase in pyramidal cell excitability. Patterns of afferent stimuli which activate pyramidal cells to reproduce the theta rhythm observed in the hippocampus under physiological conditions, have been shown to induce LTP-like enhancement of synaptic responses in vitro. The aim of this study was to investigate the presence of EPSP-spike potentiation and/or changes in pyramidal cell excitability during the long-term potentiation induced in the CA1 region of rat hippocampal slices by theta-like patterns of stimuli: the primed burst and the patterned stimulation. Using extracellular recording, a significant leftward shift in the EPSP-spike relationship was found 30 min after primed burst or patterned stimulation. The magnitude of EPSP-spike potentiation induced by patterned stimulation was similar to that produced by high-frequency stimulation. Both were significantly greater than that induced by a primed burst, indicating that only a subset of pyramidal cells were potentiated by this kind of afferent activation. Modifications in synaptic efficacy and cell excitability brought about by a primed burst were investigated in 25 intracellularly recorded pyramidal cells. Consistent with extracellular results, it was found that only 11 out of 25 neurons receiving a primed burst were potentiated. In these cells the increase in probability of firing action potentials elicited by synaptic activation with test shocks was accompanied by enhanced cell excitability, but not by an increase in EPSP slope. High-frequency stimulation delivered 40 min after a primed burst invariably increased the EPSP slope, the probability of firing upon synaptic stimulation, and the excitability of cells. The presence of EPSP-spike potentiation and of increased excitability of potentiated cells during the primed burst-induced long-term potentiation strengthen the suggestion that theta pattern-induced synaptic potentiation can be considered similar to high-frequency stimulation and long-term potentiation and supports the notion that the EPSP-spike potentiation is a constitutive characteristic of long-term potentiation.
Action Potentials↗
Intracellular pH changes produced by glutamate uptake in rat hippocampal slices.
1. The mean intracellular pH in area CA1 of rat hippocampal slices was monitored fluorescently after loading the cells with the dye BCECF-AM. 2. Including L-glutamate in the solution superfusing the slice led to the intracellular pH becoming more acid. This acidification had a roughly Michaelis-Menten dependence on the superfused glutamate concentration with a half-maximal dose around 200 microM: this value must overestimate the glutamate concentration at most of the cells, which will be reduced by uptake. 3. The glutamate-evoked acidification was not significantly reduced by blockers of glutamate-gated ion channels [6-cyano-7-nitroquinoxaline-2,3- dione (CNQX) and D-aminophosphonovalerate (APV)] nor by blockers of gamma-aminobutyric acid (GABA)- and glycine-gated channels (picrotoxin and strychnine), and so was not produced by H+ entry through alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) or N-methyl-D-aspartate (NMDA) receptor channels nor by HCO3- exit through the chloride channels controlled by GABA or glycine. 4. The glutamate-evoked acidification was not reduced by tetrodotoxin (TTX), ruling out the possibility of it being generated by action potentials. It was also unaffected by saturation of presynaptic L-amino-4-phosphonobutanoate (AP4) receptors with AP4. 5. In the presence of blockers of glutamate-, GABA-, and glycine-gated channels, the acidification showed the pharmacology of glutamate uptake and was reduced by a glutamate uptake blocker. 6. The glutamate-evoked acidification showed an ion dependence similar to that of glutamate uptake. It was abolished by removal of extracellular sodium and was reduced by raising the extracellular potassium concentration. It was unaffected by blockers of Na+/H+ exchange (amiloride) and Na+/HCO3- cotransport [4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)] and so was not produced by the Na+ influx accompanying glutamate uptake changing the activity of these carriers. 7. These data show that the glutamate uptake carrier acidifies hippocampal cells, possibly because it transports a pH-changing anion out of the cell as in salamander glial cells. Glutamate uptake may thus contribute to activity-induced pH changes in the nervous system.
Acid-Base Equilibrium↗
[Spontaneous closure of coronary fistulas: a possible prognostic role of the site of drainage].
The case of a 34 month-old infant with cardiac murmur and echocardiographic signs of coronary artery fistula is presented. Cardiac catheterization was performed, revealing a right coronary artery-to-right ventricle fistula, and a significant left-to-right shunt. At 4.0 years of age she underwent a repeated catheterization, showing complete spontaneous closure of the fistula. Review of the literature shows that fistulas draining into the right ventricle have some chance to close spontaneously. Accordingly, clinical approach should therefore be considered.
Age Factors↗
Long-term experience with high-flux polysulfone in hemodialysis.
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Biocompatible Materials↗
Oversize balloon atrial septal dilatation: early experience.
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Catheterization↗
Glutamate uptake from the synaptic cleft does not shape the decay of the non-NMDA component of the synaptic current.
To study the role of glutamate uptake at central glutamatergic synapses, we used the uptake blocker L-transpyrrolidine-2,4-dicarboxylate (PDC). The effects of PDC on the glutamate uptake current in salamander retinal glia indicated that PDC competes with glutamate for transport on the uptake carrier and that 300 microM PDC should significantly reduce the uptake of glutamate during the synaptic current. In isolated rat hippocampal neurons, 300 microM PDC did not affect non-N-methyl-D-aspartate (NMDA) receptor currents, but reduced NMDA receptor currents by 30%. In hippocampal and cerebellar slices, whereas 300 microM PDC reduced the NMDA component of excitatory synaptic currents by 50%, it reduced the non-NMDA component only slightly with no change in its decay time constant. Thus, the decay rate of the non-NMDA component is not set by the rate of glutamate uptake from the synaptic cleft into the presynaptic terminal.
Animals↗
Iopamidol in cardioangiography: a retrospective, multicenter study. Part I. Adult patients.
To evaluate the occurrence of complications during diagnostic or interventional catheterization a retrospective analysis of catheterization procedures in 12 Italian laboratories using the nonionic contrast medium (CM) iopamidol (370 mgI/ml) was performed. Data obtained on 26,219 patients greater than or equal to 14 years are presented. The overall complication rate was 1.89% (485/26,219). The overall mortality rate was 0.1% (27/26,219). Procedure related complications were 389 (1.48%) and CM related complications were 106 (0.4%). No death was attributed to CM. Ventricular fibrillation (VF) rate was 0.11% comparable to the low rate observed with nonionic CM in other studies and less than the rate observed in surveys concerning the use of ionic CM. Fifty-seven thrombotic events were recorded (0.22%), a rate comparable with other surveys with ionic and nonionic CM. The total complication rate (6.1%), the rates of coronary occlusion (1.34%), myocardial infarction (0.37%) and urgent coronary artery by-pass grafting (0.5%) in 1,348 coronary angioplasties were lower than those recorded in previous surveys. These data confirm a good tolerability and no increased risk of VF and thrombotic events with iopamidol in cardiac catheterization.
Adult↗
Iopamidol in cardioangiography: a retrospective, multicentre study. Part II. Paediatric patients.
To evaluate the complication rate in paediatric cardioangiography with the nonionic contrast medium iopamidol data on 8,166 procedures were retrospectively collected in 12 centres. The overall complication rate was 3.78% (309/8,166). 3.44% were related to the procedure, and 0.34% to the contrast medium. The mortality rate varied with age. It was higher in patients less than 2 months (0.38%) than in patients greater than 2 months-2 years (0.06%) and in patients older than 2 years (0.03%). The total complication rate was higher than the one observed in a similar retrospective analysis performed in adult patients (1.89%). This difference is probably due to higher risk conditions of the younger patients. However the contrast medium related complication rate (0.34% vs 0.4%) and the mortality rate (0.11% vs 0.1%) were comparable, confirming the good tolerability of iopamidol in cardiac catheterisation also in paediatric patients.
Age Factors↗
Infundibular septal defect with severe aortic regurgitation: a new surgical approach.
Aortic regurgitation associated with prolapse of an aortic cusp and an infundibular septal defect is caused by the lack of anatomical support for the aortic annulus by the conal septum. This fact is taken into consideration in the new surgical approach that we performed in 5 children 3 to 16 years of age with infundibular ventricular septal defect and severe aortic regurgitation. The ventricular septal defect is closed by a patch anchored to another patch through the prolapsed cusp. This second patch is pulled up with the prolapsed cusp and is then fixed in the aortic wall. In all 5 patients, all clinical signs of aortic insufficiency disappeared, and only minimal aortic regurgitation could be demonstrated by color Doppler mapping.
Adolescent↗
Serotonin blocks the long-term potentiation induced by primed burst stimulation in the CA1 region of rat hippocampal slices.
The effect of 5-hydroxytryptamine on the induction of long-term potentiation by a train of high frequency pulses (100 Hz; 1 s) or by a stimulation consisting of one burst of five pulses at 100 Hz delivered 170 ms after a single pulse (primed burst) was investigated in the CA1 region of the rat hippocampal slice in vitro with extracellular recordings. Superfusion with 5-hydroxytryptamine (3-30 microM) produced a concentration-dependent decrease in amplitude of the population spikes evoked by test stimuli. The presence of 5-hydroxytryptamine (30 microM) did not affect the magnitude of long-term potentiation produced by the high-frequency stimulation but it prevented the long-term potentiation induced by a primed burst. The action of 5-hydroxytryptamine was mimicked by the 5-hydroxytryptamine1A agonist 5-carboxamidotryptamine (0.3 microM) and blocked by the 5-hydroxytryptamine2/5-hydroxytryptamine1A antagonist spiperone (3 microM) or by the 5-hydroxytryptamine1/5-hydroxytryptamine2 antagonist methiothepin (1-10 microM). The selective 5-hydroxytryptamine2 antagonist ritanserin (1 microM) did not antagonize the block of long-term potentiation produced by 5-hydroxytryptamine. The selective 5-hydroxytryptamine3 antagonists (3-tropanyl)-1H-indole-3-carboxylic acid ester (ICS 205-930; 1 nM) and ondansetron (GR-38032; 30 nM) did not affect the reduction in the population spike produced by application of 5-hydroxytryptamine. In contrast, a primed burst delivered at the fifth minute of 5-hydroxytryptamine application in the presence of a 5-hydroxytryptamine3 antagonist induced a long-term potentiation.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Uremic inhibitors of erythropoiesis: a study during treatment with recombinant human erythropoietin.
The effects of increasing amounts of uremic sera (US) on the growth of erythroid progenitor cells [burst-forming unit erythroid (BFU-E)] collected from peripheral blood of normal subjects were evaluated to assess the potential role of uremic inhibitors of erythropoiesis during a treatment with recombinant human erythropoietin (r-HuEpo). US were collected from 8 patients on regular dialysis with marked anemia (Hb 6 +/- 0.5 g%) before and after a treatment with high doses of r-HuEpo (from 300 to 525 U/kg/week). Standard cultures for BFU-E were performed in alpha-metylcellulose with fetal calf serum (FCS) and 4 U/ml of r-HuEpo (Cilag, Ortho). In successive cultures, US were added at increasing amounts to the standard culture in order to assess a possible inhibitory effect on BFU-E growth. Finally, in order to assess a possible lack of stimulatory factors, we partially substituted FCS with US. The addition of US collected either before or after therapy with r-HuEpo to the standard culture had no effect on the growth of BFU-E. Vice versa, the number of cultured BFU-E decreased when FCS was partially substituted with US collected before r-HuEpo. This effect was not evident when FCS was partially substituted with US collected after r-HuEpo. No significant differences were recorded in the tested sera collected before and after therapy considering erythropoietin levels and amino acid levels. We hypothesized that some other factors with erythropoietic stimulatory activity (burst-promoting activity?) may be deficient in uremic patients with marked anemia and can be induced during therapy with r-HuEpo.
Adult↗
Circulating burst-forming-unit erythroid and the responsiveness to recombinant human erythropoietin in patients on regular hemodialytic treatment.
The dose of recombinant human erythropoietin (r-HuEpo) required to correct anemia of end-stage renal disease varies among patients. The possible factors that interfere with the responsiveness to r-HuEpo were not completely known. In 32 patients on regular hemodialytic treatment with marked anemia (Hb 5.6 +/- 0.7 g/dl), we evaluated circulating erythroid progenitor cells [burst-forming-unit erythroid (BFU-E)], erythropoietin, ferritin, folate and 1-84-parathormone levels before r-HuEpo therapy. In 12 patients, the aluminum levels after deferoxamine were also evaluated. The possible correlation between these factors and the response to r-HuEpo therapy was then evaluated. The number of circulating (c) BFU-E was highly variable (521 +/- 447 colonies/ml of blood; normal level 742 +/- 192) and does not correlate with erythropoietin, ferritin, folate, 1-84-parathormone or aluminum levels. A direct correlation between basal cBFU-E and the responsiveness to r-HuEpo therapy was recorded while no correlation was found with the other analyzed parameters. We hypothesized that low basal cBFU-E (interleukin-3 deficiency?) could reduce the response to r-HUEpo because of failure of this hematopoietic stem cell compartment to replenish the pool of more mature erythropoietic progenitor cells during the phase of accelerated maturation induced by r-HuEpo.
Anemia↗
Balloon occlusion of the ascending aorta for angiographic visualization of the coronary arteries in neonates with transposition of the great arteries.
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Angiography↗
Evaluation of the Damus-Kaye-Stansel operation in infancy.
Thirteen patients, 12 of whom younger than 2 years, underwent a Damus-Kaye-Stansel procedure for complete transposition of the great arteries, ventricular septal defect, or double-outlet right ventricle and subpulmonary ventricular septal defect. In 6 patients, associated cardiac anomalies caused systemic flow obstruction. There were six hospital deaths (mortality rate, 42%). In a mean follow-up period of 57 months, 5 of 7 survivors required relief of right ventricular hypertension through conduit replacement or enlargement (4 patients) or conduit valve balloon dilation (1 patient). The aortic valve became regurgitant in 2 patients in whom it had been left in potential connection with the right ventricle. One patient has moderate pulmonary valve regurgitation. The main advantage of the Damus-Kaye-Stansel procedure is that it avoids coronary relocation; also, the spatial relationship of the great arteries and the coronary anatomy do not affect its feasibility. One drawback is the need for a conduit in infancy. Our present indication for Damus-Kaye-Stansel procedure is confined to double-outlet right ventricle with subpulmonary ventricular septal defect; 5 of 6 patients survived repair in this series. Possible indications are for patients with associated subaortic obstruction or unusual coronary arrangements. Fresh or cryopreserved homografts as extracardiac conduits and primary closure of the subaortic area may reduce the need for reoperation after Damus-Kaye-Stansel procedure.
Blood Vessel Prosthesis↗
Balloon dilation of postsurgical subaortic obstruction.
Two children aged 10 and 5.5 years underwent balloon dilation for postsurgical subaortic obstruction. The outcome and the role of this procedure are discussed.
Aortic Stenosis, Subvalvular↗
Percutaneous balloon valvuloplasty of pulmonary valve stenosis, dysplasia, and residual stenosis after surgical valvotomy for pulmonary atresia with intact ventricular septum: long-term results.
Eight-six children (aged 20 days to 14 years, 20 under age 1 year) underwent 94 percutaneous balloon valvuloplasty for pulmonary valve stenosis. The patients were divided into three groups: typical pulmonary valve stenosis (71), pulmonary valve dysplasia (9), and residual stenosis after surgical valvotomy for pulmonary atresia with intact ventricular septum (PAIS) (6). Each of the three groups was divided into two subgroups. In the early cases, balloon catheters with diameter 10-20% exceeding pulmonary valve annulus were used and the drop of the gradient was 39.5%. In the later cases, balloon diameters 30-40% greater than the valve anulus or double balloons were used and a drop of 66.7% in the RV-PA pressure gradient was achieved. The dilation in patients with dysplastic valve and residual stenosis after surgical valvotomy for PAIS was less effective. Doppler echocardiography was the technique used to evaluate residual gradient. Six months to 4 years follow-up demonstrated a persistent decrease of the valve gradient.
Adolescent↗